Combustion chamber



June 17, 1947. K. v. SMITH COMBUSTION CHAMBER Filed June 9, 1944ATTORNEY Patented June 17, 1947 2,422,213 COMBUSTION CHAMBER Keith v.Smith, Wilkinsburg, Pa., assignor to Westinghouse Electric Corporation,East Pittsburgh, Pa., a corporation of Pennsylvania Application June 9,1944, Serial No. 539,498

3 Claims.

This invention relates to' power plants and particularly to the mannerof mounting fuel nozzles in a gas turbine power plant and it has for anobject to provide an improved device of the character set forth.

The present invention, while not limited thereto, is particularlyadapted to be used in a gas turbine power plant like that disclosed inthe patout to Stewart Way, No. 2,405,723 issued August 13, 1946, andassigned to the assignee of the present invention. A power plant of thetype dis closed in the mentioned Way patent includes an air compressor,air heating apparatus, a gas turbine, and a propulsion jet nozzle allhoused within a streamlined tubular casing. A plant of this character isparticularly suitable for propelling aircraft at high speeds andoperates generally as follows: Air enters the forward end of the tubulareasing, which is pointed in the direction of flight, and is compressedin the compressor, the compressed air is then heated in the heatingapparatus by combustion of fuel supported by the compressed air.The'resulting motive fluid, comprise ing the products of combustion andexcess compressed air, drives the turbine and is then discharged throughthe propulsion nozzle as a jet, the reaction of which serves to propelthe aircraft. The turbine extracts at least suflicient power from themotive fluid to drive the compressor and auxiliaries. Thefuel issupplied to the air heating apparatus, under the control of a throttlevalve, by means of a pump which is preferably driven by the turbine. I

In a plant of this character, fuel, such as gasoline, is atomized bymeans of fuel nozzles in a combustion chamber or chambers where itreadily mixes with the compressed air supplied to the chamber and isignited by suitable means such as spark plugs mounted in the combustionchamber.

The present invention is particularly concerned with the location .ofand manner of mounting the fuel nozzles. the present invention thenozzles are readily removable for inspection, cleaning and replacementand are arranged so that the fuel issuing from the nozzles isimmediately and throug hly mixed with fresh compressed air entering thecombustion chamber so that continuous and even burning of the air-fuelmixture is obtained.

It is, accordingly, a further object of the invention to provide animproved fuel nozzle and manner of mounting the same in a. combustionapparatus to permit ready removal and replacement of the nozzle.

It is another object of the invention to provide In accordance with animproved air heating apparatus in which rapid and thorough intermixingof air and fuel are obtained.

These and other objects are effected by the invention as will beapparent from the following description and claims taken in connectionwith the accompanying drawings, forming a part of this application, inwhich:

Fig. 1 is a side elevational view of a gas turbine power plant in whichthe present invention is incorporated, portions of the outer casingstructure being broken away to show certain details of construction;

Fig. 2 is a fragmentary sectional view shown on an enlarged scale of thecombustion apparatus of the plant shown in Fig. 1;

Fig. 3 is a transverse sectional view taken substantially on the lineIll-III of Fig. 2;

Fig. 4 is a sectional view through the portion of the inner wall of thecombustion chamber substantially opposite the fuel atomizing nozzles;

Fig. 5 is a sectional view taken substantially on the line VV of Fig. 4;and

Fig. 6 is a view similar to Fig. 5 illustrating a modification.

The power plant shown in Fig. 1 comprises in general an outer casingstructure l0 open from end to end and a central core structure llproviding an axial flow passage l2 which extends fore and aft withrespect to the aircraft in which it is mounted.

The central core structure II is supported by the casing structure alongits longitudinal axis and includes a hollow fairing cone l4 definingwith the forward or left end, as viewed in Fig; 1, of the casing l0 anair inlet l5 of the flow passage I2. The fairing cone ll houses a fuelpump, generally indicated l6, and other auxiliary apparatus (not shown)driven by the turbine. The core structure also includes an axial flowcompressor H, a gas turbine l8 and an axially movable tailpiece l9 whichdefines with\ the rear end of the casing structure I, an adjustablepropul sion nozzle 2|. The intermediate portion of the core structure Hbetween the-compressor I l and the turbine I8 comprises an inner wallstructure 22 which houses a; shaft 23 connecting the rotor of turbine l8and the rotor of the compressor I1.

This inner wall structure 22 defines with the outer casing structure l0,an annular space 24 which connects the compressor blade passage with theturbine blade passage and houses the air heating or combustionapparatus.

The annular space 24 is provided with a suitable combustion chamber 25,such as shown in the copendingapplication of Fay et al., Serial No.511,468, filed on November 23, 1943, and assigned to the assignee of thepresent invention, for heating the air compressed by the compressor.

In the embodiment illustrated, the combustion chamber 25 comprises aninner cone 26 and an outer cone 21 tapering in opposite directions andsecured together at their upstreamends by an annular ring 28 of Vsection which serves to divide the stream of air discharging from thecompressor. The ring 28 is provided with a bracing ring 29 which closesoff the forward end of the chamber 25. The downstream ends 30 and 3| ofthe cones 26 and 21, respectively, are se- 'cured to the inner wallstructure 22 and outer casing l0, respectively, for supporting thecombustion chamber in the casing. The walls of the inner and outer conesare perforated, having circumferentially spaced, axially extending rowsof holes 32. The holes are preferably of progressively increasing sizein the downstrearrr direction and serve to admit the compressed air intothe combustion chamber.

In the mentioned copending application of Way et al., Serial No.511,468, filed on November 23, I943, a plurality of fuel atomizingnozzles are mounted in the closedend of the combustion chamber anddirect the fuel axially of the combustion chamber. Suitable ignitionmeans, such as spark plugs mounted downstream of the nozzles ignite theair-fuel mixture. It is a feaber directly into the spray cone 52 of thenozzle causing considerable turbulence and effecting an immediate mixingof the air and fuel. The stream of air flowing through the hole 5| alsofunctions to prevent any fuel bubbles, which might stop the flow of oil,from forming on the nozzle tip as might occur when the fuel is under lowpressure.

If desired, small scoops 5la opening in a downstream direction andformed about the openings ture of the present invention to mount thefuel.

atomizing nozzles, so that they may be readily removed for cleaning orinspection, in a very simple, inexpensive manner and to locate large airadmission openingsin the combustion chamber walls so that immediate andthorough mixing of the air and fuel is obtained. The ignition means arealso located so that the possibility of stray air currents extinguishingthe spark before it ignites the air-fuel mixture is substantiallyprevented.

The outer casing I0 is provided with a row of large openings 33,corresponding in number to the number of fuel nozzles,'and providingaccess to an inner conical casing structure 34 which defines with theinner wall structure 22 a diffuser 35 leading from the compressor H tothe combustion chamber 25. In line with each of the openings 33 thecasing 34 is provided with a threaded opening 40, each of which receivesa removable fuel atomizingnozzle, generally indicated 36. Any desirednumber of nozzles may be provided. The nozzles 36 each comprise a sleeve.31 removably threaded into an opening 40 and having a shoulder portion39 adapted to clamp a gasket 4| to the bulkhead 34 to provide afluidtight seal at theopening 49. Immediately above the shoulder 39 thesleeve 36 is preferably provided with a polygonal portion 42 to receivea wrench for tightening and removing the fuel nozzle.

The inner end of the sleeve 31 is internally threaded and removablyreceives a strainer 44 and a nozzle head 45 which projects intoanopening 46 provided in the outer cone 21 of the combustion chamber.The outer end of the sleeve is recessed and internally threaded, thebottomof the recess being shaped to provide an inverted flare seat 41.Fuel is supplied to the nozzle 35 by means of a pipe 48 extending from amanifold 49 and clamped to the inverted flare seat 41 by means of a nut56, the end of which corresponds in shapeto the seat 41 for effecting a5| 'as shownin Figs. 4, 5 and 6 may be provided so that the momentum ofthe air flowing from the compressor is efl'ective to increase thevelocity of the air flowing through the openings 5|. Fig. 4 represents atransverse section through the inner cone 26 of the combustion chambertaken through the approximate, centers of'the openings 5|, the scoops5la in this figure being pressed out of the wall 26 in forming theopenings 5|. Alternatively, the scoops may be formed as separate members5|b secured, as by spot welding, to the outer surface of the inner cone26 around the opening 5| as shown in Fig. 6. r

Ignition of the fuel and air mixture is obtained by means of spark plugs53, or other suitable ignition means, which are preferably mounted inthe plane of and between the fuel nozzles 36 as shown in Fig. 3. v

To insure a continuous flow of the fuel and air mixture through thecombustion chamber and to prevent stagnation of the mixture in: the

upstream end of the combustion chamber, a rowof small openings 54 maybeprovided'upstream of the large openings 5|.

From the structure described above, it will be seen that the fuelnozzles 36 are easy to remove and replace and that the relation of thelarge air openings 5| directly opposite each nozzle provides thoroughmixing of the air and fuel and also prevents formation of fuelbubbles'at the nozzle tip which might tend to restrict the flow oratomization of the fuel.

While the invention has been shown in but one form, it will be obviousto those skilled in the art that it is not so limited, but issusceptible of various changes and modifications without departingfromthe spirit thereof, and it is desired, therefore, that only suchlimitations shall be placed thereupon as are'specifically set forth inthe appended claims.

What is claimed is:

1. In.a gas turbine power plant wherein an outer casing supports aninner casing and has secured thereto andinwardly thereof an intermediateconical casing, said inner. casing having a portion coaxial with theconical casing and which is oppositely coned with respect to the latterand cooperates therewith to provide a' diffuser for air received at highvelocity; means including oppositely-coned inner and outerforaminouswall elements connected byan apical junction portion extendingreentrantly into the difi'user and defining a combustion chamber. whichis coaxial with the diffuser and which diizers each of whichextendsthroughaligned openings formed in the outer casing, theintermediate conical casing, and the outer conical wall element so as tobe accessible externally of the outer casing and to discharge atomizedfuel into the combustion chamber; and means for detachably connectingand disconnecting each atomizer to tion thereof by effort appliedexternally of the outer casing.

2. The combination as claimed in claim 1 wherein the means providing forconnection and disconnection of each atomizer with respect to theintermediate conical casing is comprised by cooperating inner conicalcasing and atomizer threads, an abutment formed on the atomizer forengagement with the outer surface of the inner conical casing, and aportion for engagement by a wrench applied externally of the outercasing.

3. Combustion apparatus comprising a tubular outer casing; a corestructure surrounded by and spaced radially from said outer casing, saidcore structure and outer casing defining a circumferentially-continuous.passage for flow of air; inner and outer tubular well structures insaid air flow passage in side-by-side relation,-said wall structuresbeing radially spaced throughout a major portion of their length fromeach other and from the core structure and the outer casin with thespace between said tubular wall structures providing acircumferentially-continuous combustion chamber blanketed inwardly andoutwardly by circumferentially-continuous air flow passages, said outertubular casing and said outer tubular wall structure having an alignedpair of openings therein; and a fuel nozzle positioned in said pair ofopenings for admitting fuel to said combustion chamber, said nozzlebeing insertable and removable from exteriorly of said outer casing,said inner tubular wall structure being provided with one or moreapertures so disposed as to admit air from the inner air flow passage tothe combustion chamber directly into the fuel admitted by the nozzle.

KEITH V. SMITH.

I REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Name Date Preston Nov. 21, 1916 Lasley Apr. 19,1932 Lysholm July 6, 1937 Jendrassil: May 27, 1941 FOREIGN PATENTSNumber Number 416,030 Add. 13,715

